Search

Presents comments and suggestions for the publication the journal "Communications of the ACM." Proposition for the publication of papers; Criticisms on the article of Peter Naur in the December 1975 issue entitled "Programming Languages, Natural Languages, and Mathematics"; Comments on the contribution of Wallace E. Lin in the January 1976 issue.

The article provides information on the upcoming symposiums related to the computer engineering in 1966. A one-day symposium will be sponsored by ACM, SIAM and Florida State University on March 14 on "The Recommended Impact of Computer Applications on the Undergraduate Mathematics Curriculum." The four New York Metropolitan Area chapters will hold a one-day symposium in New York City on March 18. A session of invited papers will be devoted to "The Application of Computers to the Problems of a Metropolitan Society." In addition, a session of contributed papers on any topics in the computer field is now in the process of being organized . Automatic Data Processing exhibits and workshops headline the Federal Government Accountants Association 15th National Symposium, in Minneapolis, June 15-17. Topics include "Case Studies in ADP," "Programming: The Modern Budget Officer's Tool," and "The Future of Computers in the Federal Government." The Instrument Society of America (ISA) has invited papers for presentation at the 21st Annual ISA Conference and Exhibit, to be conducted October 24-27 in New York City. Theme of the meeting is "Instrumentation for an Urban Society."

This paper provides performance results using the SPERRY UNIVAC 1100 Series linear programming product FMPS to solve a set of 16 real-world linear programming problems. As such, this paper provides a data point for the actual performance of a commercial simplex algorithm on real-world linear programming problems and shows that the simplex algorithm is a linear time algorithm in actual performance. Correlations and performance relationships not previously available are also provided. [ABSTRACT FROM AUTHOR]

Several letters to the editor are presented in response to several articles, including "Performance Results of the Simplex Algorithm for a Set of Real-World Linear Programming Models" in the March 1982 issue, and "A Critique of the Foundations of the Hoare Style Programming Logics."

This article presents information about contributions of Alan Turing in the field of computer science. Turing was a brilliant mathematician who showed that computers could not completely prove mathematical assertions. This connection between computers and mathematics was later used to develop a mathematical foundation for computer science, comparable to mathematical foundations for physics and other sciences. Born in 1912, Turing was accepted by Cambridge University, Cambridge, England in 1930 to study mathematics, and became a Fellow in 1934 at the age of 22, completing a dissertation that extended the group theory models of Von Neumann. After its beginning with Turing's pioneering paper in 1936, computer science emerged as a mature discipline in the 1960s, when universities nationwide started offering it as an undergraduate program of study. The new discipline of computer science viewed computation as information processing, a transformation of input to output--where the input is completely defined before the start of computation, and the output provides a solution to the problem at hand.

The article reports on finding all subgraphs of an undirected graph [H]. A maximal complete subgraph is also called clique which refers to a complete subgraph that is not included in any other complete subgraph. According to the authors, a research paper was released wherein descriptions of techniques to find maximal complete subgraphs are provided. The authors discussed two algorithms using a branch-and-bound technique so that there will be no clique. The first algorithm produces cliques in lexicographic order while the second is derived from the first algorithm.

This article presents information about a research paper which examines the functions realizable with word-parallel logical and two's complement addition instructions. H. Tim Gladwin has shown a number of programming tricks involving binary numbers, some of which are represented in this paper. It was assumed that two's complement (or unsigned) arithmetic is used, and that overflow may be ignored. Gladwin's motivation is to provide simple tests to determine whether or not a number is of a certain binary form. Leslie Lamport gives similar tricks for comparison of integers when several are packed in a single word. In the discussed paper, a theorem is described from which one may easily deduce whether or not a coding trick of this general class exists for computing a given function, followed by an efficient implementation of sign propagation that does not use shifting instructions or branching instructions. In this theorem, sign propagation means considering a certain bit position in a word to be the sign bit in the two's complement representation of a number.

The article presents a list of upcoming symposiums on computer science and technology in the U.S. Texas A&M Instrumentation Symposium for the Process Industries will be held in Texas University on January 19-21, 1966. The American Mathematical Society Annual Meeting, cosponsored by the Mathematics Association of America, will be held in Chicago, Illinois, on January 24-28, 1966. The 1966 Annual Symposium on Reliability will be held at the Sheraton-Palace Hotel, San Francisco, California, on January 25-27, 1966. The International Symposium on Information Theory will be held at the University of California, Los Angeles, on January 31-February 3, 1966. The 6th Annual Computing Center Conference, ACM-SIAM-FSU Symposium will held on March 12-19, 1966 at Florida State University, Tallahassee. The Symposium on Simulation Languages will be held on March 17-18, 1966, at the University of Pennsylvania, Philadelphia. The 4th International ISA Aerospace Instrumentation Symposium will be held at the College of Aeronautics, Cranfield, England, on March 21-25, 1966.

Suppose that one observes an incomplete subset of entries selected from a low-rank matrix. When is it possible to complete the matrix and recover the entries that have not been seen? We demonstrate that in very general settings, one can perfectly recover all of the missing entries from most sufficiently large subsets by solving a convex programming problem that finds the matrix with the minimum nuclear norm agreeing with the observed entries. The techniques used in this analysis draw upon parallels in the field of compressed sensing, demonstrating that objects other than signals and images can be perfectly reconstructed from very limited information. [ABSTRACT FROM AUTHOR]

The article presents a conversation with educationists Seymour Papert, Marvin Minsky and Alan Kay on educational reform, artificial intelligence, computer science and human-computer interaction. The importance of the computer is how you learn mathematics, and how it allows children to think about powerful ideas in mathematics. Children are capable of learning plenty more mathematics than anyone gives them credit for with or without a computer. The most important thing in learning is copying how other people think. The way to learn something hard is by getting new ideas. Programming is the most powerful medium of developing the sophisticated and rigorous thinking needed for mathematics, for grammar, for physics, for statistics, and all the hard subjects. Programming should be a key part of the intellectual development of people growing up. The idea of programming itself is something in evolution so it will not mean exactly what it is thought to mean.

A new technique of program transformation, called "recursion introduction," is described and applied to two algorithms which solve pattern matching problems. By using recursion introduction, algorithms which manipulate a stack are first translated into recursive algorithms in which no stack operations occur. These algorithms are then subjected to a second transformation, a method of recursion elimination called "tabulation," to produce programs with a very efficient running time. In particular, it is shown how the fast linear pattern matching algorithm of Knuth, Morris, and Pratt can be derived in a few steps from a simple nonlinear stack algorithm. [ABSTRACT FROM AUTHOR]

A list of a number of natural developments for the field of algebraic manipulation is given. Then the prospects for a general theory of functions defined by ordinary differential equations are discussed. The claim is made that recent developments in mathematics indicate that it should be possible to algorithmically generate many properties of solutions to differential equations. Such a theory is preferable to a less general effort to make algebraic manipulation systems knowledgeable about the usual special functions (e g exponential, hyper geometric) [ABSTRACT FROM AUTHOR]

Numerical mathematics is viewed as the analysis of continuous algorithms. Four of the components of numerical mathematics are discussed. These are: foundations (finite precision number systems, computational complexity), synthesis and analysis of algorithms, analysis of error, programs and program libraries. [ABSTRACT FROM AUTHOR]

Investigates how the special structure of matrices can be described and utilized for mathematical programming. Symbol manipulation of matrix expressions; Extension of matrix operators to sequence operators and cumulative operators.

The article discusses a study published within the journal that demonstrated a model for analyzing and describing the efficiency of functional algorithms. Topics discussed include the accuracy and complexity of cache-aware estimates of real-world performance, the use of asymptotic notation to describe costs, and cache-oblivious algorithms as an example of the use of abstraction to combine accurate cost estimates with tractability. Also mentioned are the correspondence between allocation order and memory order, the expression and analysis of efficient cache-oblivious functional algorithms, and the ability of computer scientists to improve both the simplicity and accuracy of models.

The article presents schedules of events related to the Association for Computing Machinery (ACM). The annual meeting of the MUMPS Users' Group will be held during June 7-11, 1982, in Denver, Colorado. The Workshop on Management and Office Information Systems will be held in Chicago during June 28-30. The International Conference on Advanced Automation will be held during July 13-15 in Taipai, Taiwan. The 7th Symposium of Operations Research will be held during August 19-21. Eurographics 82 will be held during September 8-10. The ACM-IEEE Fifteenth Annual Workshop on Microprocessing will be held in Palo Alto, California, during October 4-7. The 1982 IEE Professional Communication Society Conference will be held during October 6-8.

The purpose of this note is to report computational experience additional to that recently summarized by Gue et al., with two algorithms for the zero-one linear programming problem. An error in Gue's paper is corrected. The utility of one of the algorithms as a suboptimizer is indicated. [ABSTRACT FROM AUTHOR]

The article presents abstracts of some of the papers that were published in the "Journal of the Association for Computing Machinery." A number of observations and comments are directed toward suggesting that more than the usual engineering flavor be given to computer science. The engineering aspect is important because most present difficulties in this field do not involve the theoretical question of whether certain things can be done, bat rather the practical question of how can they be accomplished well and simply. The teaching of computer science could be made more effective by various alterations, for example, the inclusion of a laboratory course in programming, the requirement for a strong minor in something other than mathematics, and more practical coding and less abstract theory, as well as more seriousness and less game playing. Recursive formulas for the numerical evaluation of the real convolution integral are derived for the case in which the impulse response is given analytically. These formulas require considerably less computation time and memory space than the general time series formulas and can be effectively applied for digital simulation of continuous physical systems.

This article presents news briefs related to the Association for Computing Machinery (ACM). J.F. Traub was appointed as the chairman of SIGNUM. Traub had been chairman of SICNUM. Traub then announced that professor C.W. Gear will serve as liaison between national SIGNUM and local chapters. Professor Gear will assist existing special interest committees on numerical mathematics at the chapter level, and will endeavor to help new ones get started. The ACM Council has approved the establishment of a Special Interest Committee for File Description and Translation (SICFIDET). One of SICFIDET's initial tasks will be to compile a glossary for terminology and practice in the areas of data management and information and file description, since there is at present a great divergence as well as variety in the use of identifiers in these areas. Plans are already under way for publication of a "SICFIDET Bulletin." The publication will include discussions of problems in the correspondences between logical and physical data forms, the evolution of a file description notation, the development of techniques for automatic generation of descriptions, and the information requirements for translation among different logical and physical forms.

The article explores design-oriented mathematical practices in school and work settings. The article represents two scenes that show people working on design problems in very different places. In the first scene, a group of seventh graders have decided that separate space for tubs and wash basins in a dormitory floorplan for college students in Seattle, Washington. With savings from the redesigned bathrooms, they propose a better insulated dormitory for the colder climate of Duluth, Minnesota. The second scene shows a civil engineer leaning over paper space views of a housing development project proposed for a hilly region of California. People in both scenes combine different representations to model space and its intended use. To understand how mathematical reasoning develops to support this activity a research team compares settings at three levels of analysis. The practical goal of the article is to improve learning and teaching mathematics in grades 6, 7, and 8. This involves developing curriculum units that package together simulation environments.

The article discusses time synchronization in computer systems and presents Precision Time Protocol (PTP) as an alternative to Network Time Protocol (NTP) synchronization when cable costs are prohibitive or measurement and control system device precision is required. Topics include data packet management, local area networks, the Best Master Clock (BMC) algorithm, the use of boundary clocks in device hierarchy, security concerns, and peer delay mechanisms. Diagrams are included of a synchronization message exchange, a network stack supporting hardware timestamping, and device hierarchies.

Decoupling a logical device from its physical implementation offers many compelling advantages. [ABSTRACT FROM AUTHOR]

This article discusses that whether computer science should be recognized as a branch of science or not. Science, engineering, and mathematics combine into a unique and potent blend in our field. Some of the activities are primarily science--for example, experimental algorithms, experimental computer science, and computational science. Some are primarily engineering--for example, design, development, software engineering, and computer engineering. The scientific paradigm, which dates back to Francis Bacon, is the process of forming hypotheses and testing them through experiments; successful hypotheses become models that explain and predict phenomena in the world. Computing science follows this paradigm in studying information processes. The European synonym for computer science--informatics--more clearly suggests the field is about information processes, not computers. Computing research is rife with examples of the scientific paradigm. Cognition researchers, for example, hypothesize that much intelligent behavior is the result of information processes in brains and nervous systems; they build systems that implement hypothesized information processes and compare them with the real thing.

Discusses the development of computational and graphical techniques necessary to the solution of mathematical problems. Reasons why mathematicians are interested in computer graphics; Concept of minimal surface; Minimal surfaces with infinite area.

It Is argued that formal verifications of programs, no matter how obtained, will not play the same key role hi the development of computer science and software engineering as proofs do in mathematics. Furthermore the absence of continuity, the Inevitability of change, and the complexity of specification of significantly many real programs make the formal verification process difficult to justify and manage. It Is felt that ease of formal verification should not dominate program language design. [ABSTRACT FROM AUTHOR]

An efficient and numerically stable method is presented for the problem of updating an orthogonal decomposition of a matrix of column (or row) vectors. The fundamental idea is to add a column (or row) analogous to adding an additional row of data in a linear least squares problem. A column (or row) is dropped by a formal scaling with the imaginary unit, √-1, followed by least squares addition of the column (or row). The elimination process for the procedure is successive application of the Givens transformation in modified (more efficient) form. These ideas are illustrated with an implementation of the revised simplex method. The algorithm is a general purpose one that does not account for any particular structure or sparsity in the equations. Some suggested computational tests for determining signs of various controlling parameters in the revised simplex algorithm are mentioned. A simple means of constructing test cases and some sample computing times are presented. [ABSTRACT FROM AUTHOR]

The classical fixedpoint approach toward recursive programs suggests choosing the "least defined fixedpoint" as the most appropriate solution to a recursive program. A new approach is described which introduces an "optimal fixedpoint," which, in contrast to the least defined fixedpoint, embodies the maximal amount of valuable information embedded in the program. The practical implications of this approach are discussed and techniques for proving properties of optimal fixedpoints are given. The presentation is informal, with emphasis on examples. [ABSTRACT FROM AUTHOR]

Some social aspects of programming are illuminated through analogies with similar aspects of mathematics and natural languages. The split between pure and applied mathematics is found similarly in programming. The development of natural languages toward flexionless, word-order based language types speaks for programming language design based on general, abstract constructs. By analogy with incidents of the history of artificial, auxiliary languages it is suggested that Fortran and Cobol will remain dominant for a long time to come. The most promising avenues for further work of wide influence are seen to be high quality program literature (i.e. programs) of general utility and studies of questions related to program style. [ABSTRACT FROM AUTHOR]

A description is given of a program for computing the solution to a small number of standard numerical analysis problems to any specified accuracy, up to a limit of 2000 correct decimal places. Each computed number is bounded in an interval with a multiple precision midpoint. Arithmetic operations involving these numbers are executed according to interval arithmetic concepts, with non-significant digits automatically discarded. Details are supplied of problem specification and problem computation. [ABSTRACT FROM AUTHOR]

Presents a note on author C.J. Cheney's paper 'Nonrecursive List-Compacting Algorithm,' which appeared in the November 1970 issue of the periodical 'Communications of the ACM.' Effect of circular list consisting exclusively of non-items on the flow of the list-compacting algorithm; Structural meaning of the list-compacting algorithm.

The article announces various appointments made at the Association for Computing Machinery's Special Interest Group for Mathematical Programming, including the appointment of M.A. Efroymson as the chairman, the appointment of A. Orden as the vice-chairman, and the appointment of T. Glans as the secretary.

The article presents information on the Stochastic Linear Programming workshop held at Princeton, New Jersey, on December 2-3, 1965. The workshop was sponsored by the Special Interest Group for Mathematical Programming. The workshop was aimed at bringing active workers in the field to report on theoretical advances, new applications, and existing computer codes. Participants also shared their perspectives on new research works in the field of computer science.

The early origins of mathematics are discussed, emphasizing those aspects which seem to be of greatest interest from the standpoint of computer science. A number of old Babylonian tablets, many of which have never before been translated into English, are quoted. Discusses the early origins of mathematics, particularly aspects of great interest from the standpoint of computer science. Introduction to Babylonian mathematics; Large number of clay tablets unearthed during expeditions in the Middle East which contain mathematical calculations; Clues about the life of early computer scientists. [ABSTRACT FROM AUTHOR]

A brief history of integer and continuous nonlinear programming is presented as well as the current obstacles to practical use of these mathematical programming techniques It is forecast that the useful contributions to nonlinear programming actualls made in the next few years are more likely to he consolidations than theoretical breakthroughs These contributions are likely to be the documentation of standard test problems, construction of user oriented software, and comparisons of currently known algorithms to demonstrate which techniques are best for specific problems. [ABSTRACT FROM AUTHOR]

A computer language and a set of programs within that language are described which allow the formulating and solving of a class of space planning problems. The language is an extension of Algol and includes means to represent spaces and objects, to manipulate them, and to test the resulting arrangements according to a variety of constraints. The algorithms used to solve problems expressed in this language rely on heuristic programming. Both the language and the search algorithms are detailed. [ABSTRACT FROM AUTHOR]

A quadratic programming algorithm is described for use with the magnified diagonal method of nonlinear regression with linear constraints. The regression method is published in JACM, July 1970. [ABSTRACT FROM AUTHOR]

There are situations in the natural sciences and medicine (e.g. in electron microscopy and X-ray photography in which it is desirable to estimate the gray levels of a digital picture at the individual points from the sums of the gray levels along straight tines (projections) at a Few angles. Usually, in such situations, the picture is far from determined and the problem is to find the "most representative" picture. Three algorithms are described (all using Monte Carlo methods which were designed to solve this problem. The algorithms are applicable in a large and varied number of fields. The most important uses may he the reconstruction of possibly asymmetric particles from electron micrographs and three-dimensional X-ray analysis. [ABSTRACT FROM AUTHOR]

A method for extracting a smooth polygonal contour from a digitized image is illustrated. The ordered sequence of contour points and the connection graph of the image are first obtained by a modified Ledley algorithm in one image scan. A minimal perimeter polygon subjected to specified constraints is then chosen as the approximating contour. The determination of the minimal polygon can be reduced to a nonlinear programming problem, solved by an algorithm which takes into account the weak bonds between variables. Some examples are presented, and the corresponding computing times are listed. [ABSTRACT FROM AUTHOR]

A fast method is presented for finding a fundamental set of cycles for an undirected finite graph. A spanning tree is grown and the vertices examined in turn, unexamined vertices being stored in a pushdown list to await examination. One stage in the process is to take the top element v of the pushdown list and examine it, i.e. inspect all those edges (v, z) of the graph for which z has not yet been examined. If z is already in the tree, a fundamental cycle is added; if not, the edge (v, z) is placed in the tree. There is exactly one such stage for each of the n vertices of the graph. For large n, the store required increases as n2 and the time as γ where γ depends on the type of graph involved. γ is bounded below by 2 and above by 3, and it is shown thaT both bounds are attained. In terms of storage our algorithm is similar to that of Gotlieb and Corneil and superior to that of Welch; in terms of speed it is similar to that of Welch and superior to that of Gotlieb and Corneil. Tests show our algorithm to be remarkably efficient (γ = 2) on random graphs. [ABSTRACT FROM AUTHOR]